It is known in the art that in integrated circuit designs in which a layer of field oxide is placed over a wafer and apertures are cut down through the field oxide by reactive ion etching to form apertures for transistors, there is radiation damage in the sidewalls of the field oxide structure. This is caused by the ionizing radiation produced by the accelerations and collisions of the etch plasma ions and the material in the oxide and the substrate. This radiation has the effect of breaking silicon-oxygen bonds within the field oxide structure. These broken bonds form potential trapping sites that trap stray charge, such as that created by ionizing radiation.
As a result of this radiation damage, the regions under the terminations of the field oxide are relatively leaky due to extensive hole trapping in this oxide. There is leakage current between conductors that are in contact with the leaky surface, such as transistor sources and drains, that is greater than what otherwise would be the case and the breakdown potential between sources and drains of field effect transistors is reduced because current may flow in the parasitic transistor region formed along the edge of the field oxide structure between a source and a drain.